The result is that “the Al Qaeda cancer has also adapted to this pressure by becoming even more widely distributed, loosely knit, and geographically dispersed,” Mr. Panetta added.

“After being left on the sidelines of the momentous change that swept through the Arab world last year, they are now seeking to take advantage of the transition period to gain new sanctuary, to incite violence, and to sow instability.”

This poses a challenge for top Pentagon officials, Panetta acknowledged. One of these will be figuring out how to help small nations fight terrorists on their own soil.

In doing so, he waded into the controversy surrounding the attack on the US consulate in Benghazi. United Nations ambassador Susan Rice has come under sharp criticism from Republican lawmakers for saying in September that the administration had “decimated” Al Qaeda, saying that if that were the case, the consulate would not have been overrun.

Panetta for his part stressed in more specific terms that “Al Qaeda’s leadership ranks have been decimated.”

This, he said, includes the killing of Al Qaeda’s five top leaders in the past two and a half years.

Beyond the Benghazi controversy, Panetta said that the Pentagon will be particularly focused on completing the training of Afghan security forces in the nation where America has been at war for over a decade.

US combat forces are scheduled to depart the country in 2014, but first they must “finish the job right,” he added.

This in turn will deter extremist forces from trying to once again find a foothold in Afghanistan and to send “a very simple and very powerful message to Al Qaeda, to the Taliban, to the violent extremist groups,” Panetta argued.

“We are not going anywhere,” he said. “Our commitment to Afghanistan is long term, and you cannot wait us out.”